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Club President
I supported Toymods
Location:
Sydney
Registered:
May 2002
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 Re: 2tg head wanted preferably with 9.8comp.
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Thu, 29 August 2002 00:35
 
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Before you throw money at your mechanic you need to understand a few basic principles.
Firstly 2TG head series. There are essentially 3 types of 2TG head. The first head was the 11111-88220 head and had the small valves.
The second and more common type was is head series 88222, 88260 and 88261. (There is also a unnumbered 88262 variety)
These heads all have the same larger size valves. The 88222 head was a prodominantly carby version and did not have the webbing reinforcement in the head. If your was an EFI head it has the webbbing and is most likely a 88260 or 88261 head. These are GOOD heads !! I personally only use the 88260 and 22261 heads for this very reason !
The third type of head is the low emmisons version and has an offcentre combustion chamber according to a recent post on this forum. I don't know anything else about it I'm sorry.
ALL 2TG heads were made by Yamaha !
The yamaha head myth came about as the later model ones say Yamaha and the early ones don't. Yamaha went into partnership with Toyota when Toyota made there very first Twin cam engine for the 2000 GT in the late 1960's (1966 I think, maybe 1967 ??). The engine was the 3M (Not 3M-G, the G designation was not around then !) Toyota were not experienced with twin cam setup so they had the work done by a company that was. Can't remember when Toyota started doing there own Twin cam work but I think it was around the late 80's ! (anyone ??)
Compression !
ok bad compression can be caused by 2 main areas, The valves and the Piston rings. Anything that lets pressure escape from the compustion chamber will give poor compression.
The pistons themselves determine the Compression ratio. - ALL 2TG heads have the same size combustion chamber.
There is no such thing as a 9.8:1 Compression Head ! there are 9.8:1 Compression Pistons.
If your mechanic says you need a new head ask him why ? Sounds like he is just trying to rip you off ! The 2TG head is VERY strong and not prone to warping at worst you may need new valves which would actually cost more than a second hand head 
Any Mechainc that says you need a new head but I have one makes me suss at best !
Hope that helps.
Call me if you want any more help or info 0416 181 284.
Regards,
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